In the next five years, the Scottish independence referendum, an in/out EU referendum and a border poll on Northern Ireland could force a rethink of the entire British state.

David Cameron and Alex Salmond attend the Drumhead Service in Edinburgh, Scotland. Photograph: Getty Images.

"Devices for despots and dictators". That was Clement Attlee’s brisk dismissal of referendums and it held sway as the default view in British politics until the 1975 national referendum on continued British membership of the-then European Economic Community.

Since then, the growth in the use of referendums – and in calls to use them – seems inversely proportionate to the natural authority our risk-averse political leaders now wield. The bigger the decision, the less they want to take it.

As a result, there are now three big constitutional referendums lumbering into view over the next five years. Each is significant, but their combined effect could represent the biggest shock to the system since the break–up of the British empire.

The first is the referendum on Scottish independence. Alex Salmond knows that timing here is crucial and a date is so far elusive, although we know it is likely to be in autumn next year. Like a bee’s sting, he has one go at this. If he mistimes the vote and a majority of Scots opt for the status quo, his lifelong project will be over. It is likely, however, that a consolation prize will see extra concessions wrung out of a relieved Westminster in the form of 'devo max'. Don’t ask what that means though; as Scottish Secretary Michael Moore recently pointed out, it’s a "brand without a product".

The second referendum is more speculative. Sinn Fein is agitating for a ‘border poll’ on Northern Ireland’s constitutional status in 2016 – the centenary of the Easter Rising. So far, so predictable; that’s what an Irish republican party is for. But the Good Friday Agreement makes allowance for such votes and what makes this call slightly more intriguing is the reaction of some unionist commentators and politicians. The Democratic Unionist’s Arlene Foster recently said her party might "call [Sinn Fein’s] bluff" on the issue and support a vote. "Sinn Fein are trying to cause instability in Northern Ireland," she claimed.

"If we have the border poll then that instability goes away and, in actual fact, what we have is a very clear validation of the Union and that’s something we’re looking at at the moment."

With the recent census demographics still showing a majority of Protestants in Northern Ireland (albeit tentatively) could this be a smart move by unionists, a last decent chance to show a majority want to remain part of the UK?

The third referendum is, of course, David Cameron’s promise of an in/out EU vote following a renegotiation of Britain's membership. The PM has not set out what powers he wants to repatriate, nor if he would campaign to remain in the EU if his demands were not fully met. By 2017, the date a Conservative-led government would expect to hold the poll, both Northern Ireland and Scotland could conceivably already find themselves outside the UK.

For believers in the constitutional status quo, winning the three votes is not likely to settle grievances in the long-term. Scottish nationalism will continue to be an electorally potent reaction against Westminster rule, while the hope that Northern Ireland’s disputatious existence will be neatly resolved is the supreme elevation of optimism over reality. But winning a referendum on British membership of the EU would be a powerful fillip for pro-Europeans and would help put eurosceptics back in their box, at least for a while.

If all, or any, of these plebiscites were won by the forces of separatism, the shockwaves would force a rethink of the entire British state from its very foundations. In terms of importance, 'losing Ireland'; is the least significant, strategically and economically.

The intriguing question is which of the other two is more important: Scotland going its own way, or the whole of Britain voting to leave the EU? If both came to pass, might the new United Kingdom of England and Wales download the application form for NAFTA membership?